Hello dear. Greetings from itsohkay. Yes, you can pursue psychology after completing your graduation. After graduation, you can do MA or MSc in Psychology. However in most universities, Post graduate courses in psychology are offered only to students who have graduated in psychology. But there are few universities where the eligibility criteria is graduation in any subject. You can check IGNOU, Nalanda Open University(Patna),Tamil Nadu Open University, Institute for Psychotherapy and Management Sciences, NIMHANS(Bangalore), TISS and there would be many more.
All the best for your future.
Hope it helps.